An electrokinetic-permeable reaction barrier (EK-PRB) system was introduced in this study with hydrocalumite as the barrier material. The combined system effectively remediated the Cr(VI)-contaminated clay after a 72-h treatment, and the Cr(VI) removal efficiency increased with the initial soil moisture content. Further evidence was found that the changing soil pH value and current density were highly associated with the initial moisture content, showing its important roles in the Cr(VI) removal process. Additionally, the total Cr removal efficiency was much lower than that of Cr(VI) owing to the partial conversion of Cr(VI) to Cr(III) in the electrokinetic remediation process. Under high soil moisture conditions (40%), the removal efficiency of Cr(VI) and total Cr was 96.6 and 67.3%, respectively. Further analysis also revealed the new mineral phase, chromate hydrocalumite, for Cr fixation in the hydrocalumite barrier, which was significantly affected by the initial soil moisture content. Our results showed that the EK-PRB system with a hydrocalumite barrier is highly promising with great potential for the effective remediation of Cr(VI)-contaminated clay and engineering implementation.

Previous studies of the effects of land reclamation on the extent of seawater in coastal aquifers have assumed that the reclaimed area penetrates to the impermeable base of aquifer, and that the seawater in the aquifer is entirely contained within reclaimed sediments. The current study extends previous research into the effects of reclamation on groundwater levels and seawater extent by developing new analytical expressions for the steady‐state heads and non‐dispersive freshwater‐seawater interface for situations where reclaimed soils overly permeable aquifer material. Situations involving reclaimed soils that are more permeable or less permeable than the original aquifer are explored. Sand‐tank experiments and associated numerical simulations (in 2D cross section) were undertaken to evaluate assumptions adopted in developing the solutions, which include an empirical correction to account for dispersion effects. Sand tank solute distributions are well matched to numerical modeling results, and provide validation of analytical solutions and the associated simplifications. Application of the new solution demonstrates that both the water level rise and the seaward shift of seawater extent caused by reclamation are modified with the inclusion of the underlying permeable layer, depending on permeability contrasts and the reclaimed area size. For example, if the reclaimed soil is less permeable than the original aquifer, water level rise and the seawater extent shift are reduced with the inclusion of an underlying permeable layer. The analytical solution developed in this study can provide rapid guidance on the changes to seawater extent and groundwater levels caused by land reclamation in otherwise permeable substrate.

A quantificational calculation method of participating mass of foundation vertical vibration is presented in this paper. Vertical subsoil participating mass of strip and rectangular foundation are preliminarily calculated based on Boussinesq’s solution of subsoil additional stress and equivalent-load method. That is, the subsoil participating mass can be calculated only prescribing the isoline of additional stress. The method is suitable for adopting by corresponding codes for it avoids considering complicated influencing factors of subsoil.

One of the main challenges of drilling in the Central Andaman Sea offshore Myanmar is the mitigation of overall well integrity risk arising from weak top-hole formations. On a well drilled by one operator, conductor integrity was lost due to cratering and loss circulation while cementing which eventually led to having to re-spud the well. Almost all the offset wells drilled by the operator in the same field experienced losses in the top section interval.To meet integrity objectives for both exploration and development wells, the cementing strategy in certain cases must consider alternative solutions in addition to conventional Class G cement. In a recent project executed for one operator the cementing philosophy for the entire surface sections therefore had to be fine-tuned to incorporate the proven Optimized particle-sized distribution methodology.A proprietary coarse material made from glass beads was introduced as part of the slurry design, being used for the first time in Myanmar to further improve cement properties. On the development wells the optimized design called for pumping 10.5ppg High-performance Light-weight cement (HPLWC) lead slurry, together with a standard Class G tail.To meet operational integrity objectives, planning and risk assessments were put in place by the service company and the cementing programmes were developed to incorporate necessary mitigations against the identified risks. Plans were put in place to handle the implicit logistics requirements. Careful attention was paid to the execution given the downhole pressure sensitivities, all slurries were mixed and pumped with a degree of relative precision. This paper summarizes the design and implementation of the cementing operation which contributed positively to meeting well integrity objectives. Apart from operational success, expectations which hitherto factored in possibility of top-up jobs were exceeded; for the exploration well the critical zones were covered with good returns to seabed observed on all the cement jobs as monitored by ROV. Hard cement were tagged and drilled out from the shoe track in each case and well operations progressed without any loss of integrity issue.The paper aims to demonstrate that incorporating technology can help to improve well delivery and reduced lost time. Approximately, 18 cement jobs have been executed on the project -all successfully done. Out of these 4 top-hole cement jobs involved the use of the High-performance Light-weight (HPLWC) technology described in this paper.